Retracting mechanism for boring tools



Nov. 18, 1941. w. J. GUILD RETRACTI NG MECHANISM FOR BORING TOOLS Filed;May 22, 1959 2 Sheets-Sheet 1 Nov. 18, 1941'.

' 2 Sheets-Sheet 2 v File'd May 22, 1939 W4LDO J. GU/LD x WM 1 9 f 5 m6/ a w mv 7 laws 8 2M J 6 M v M a 1 fa M .4

, member I Like reference characters refer to like parts in PatentedNov. 18, 1941 RETRACTING. MECHANISM Foa BORING TOOLS Waldo J. Guild,Worcester, Mass, assignor to The Heald Machine Company, Worcester,Mass., a corporation of Massachusetts Application May 22, 1939, 'SerialNo. 274,927

(01. 'm -5sj) 3 Claims.

The present invention relates to boring tools, and especially to anarrangement which enables such a tool, before being withdrawn fromaworkpiece bore on which it has operated, to be retractedfor drawn inradially toward its axis of rotation, thereby preventing any scoring orscratching of the finished bore surface on said withdrawal movement.

tailed description taken in connection with the accompanying drawing, inwhich Fig. l is a view, partly in side elevation, illustrative of myinvention, with the tool retracting mechanism shown in section. Fig. 2is a sectional view along the line 2--2 of Fig. 1, through the toolretracting mechanism, taken at right angles to the section of Fig. 1.

Fig. 3 is a larger scale sectional view along the 1ine 3--3 of Fig. 2.Fig. 4 is a smaller scale sectional view along theline 4-4 of Fig. 2. Iv

Fig. 5 is a perspective View of the tool carrying the diiferent figures.

Referring to the drawings, Fig. 1 shows fragmentarily a suitable housingI having a spindle '2 journal1ed therein. Suitable bearings, not

shown, are provided in the housing for .assuring a substantiallyvibrationless rotation of the spindle 2. Any suitable means, not shown,may be employed to impart rotationto the spindle 2, the latter at itsend projecting fromthe hous ing I having a tapered portion 3 to which issecured my improved tool retracting mechanism, designated generally bythe numeral 4; the latter, as hereinafter described carries a boringtool 5. The spindle 2 is hollow and has an axially slidable rod 6arranged therein, the movements of this rod in opposite directionsprocuring alternately the retraction of tool 5 and its return tooperative position.

The tool retracting mechanism, as best shown in Figs; 1' and 2, includesa collet 8 having a tapered'bore 9 engaging with the tapered portion 3of the spindle. A clamping nut I0 holds the collet securely on the endof the spindle. The collet, as shown, has a radially extending flangeII, and on opposite sides of the flange provides cylindrical surfaces I2and I3, the former being concentricto the axis of the spindle, and thelatter being slightly eccentric, for a purpose which will hereinafterappear.

In engagement with the surface I2 is a ring I4,

which also engages with the side of the flange I I on the collet. On theother side of said flange and fitted to the surface I3 is a ring-likemember I5, having spaced forwardly-extended portions I5a and I5b (Fig.3) which provide between them a diametrical slot or passage I6, for thereception of a tool carrying member 26 (Fig. 5). A cap II engages theouter ends of the portions I5a and I51), and the several elements areheld in as sembled relation by a clamping plate I8, having a centrallypositioned stud I9 for engagement with the end of the cap. A pluralityof bolts 20 threaded at their inner ends for engagement with the ringI4, pass loosely through the collet flange II, the member I5 and'the capII, as shown in Fig. 2. In said collet flange II the openings for thepassage of bolts 20 are in the formof arcuate slots 4|, 4|, Fig. 3, fora purpose to be hereinafter described. The clamping plate I8 has aplurality of arcuate slots 2I which are large enough at one end, notshown, to'receive the heads of the bolts 20 when the plate I8 is appliedso as to register these larger portions with said bolt heads; the otherportions of said slots 2| are of less width, as shown in Fig. 2, so thatplate I8 so applied is turned through a slight angle, the bolt headswill serve to retain said plate in the position shown by Figs. 1 and 2.

The cap H has a projecting boss- 22. centrally thereof which fits thesimilarly-shaped recesses 23, 23 of the portions I5a and I5b= of memberI5 (see Fig. 2). Between said portions I5a and. 15b said cap boss 22 hasan extension 24 which projects inwardly into the passage I6, and hasspaced openings to receive coil springs 25, the outer ends of which arein contact with an inwardly-facing flat surface 38 (Figs. 3 and 5)provided by the tool-carrying member 26. The lat- I ter whichhas theform shown in Fig. 5 isposimember 26 has a notch 21, within which is received the extension 24, as well as a cam block 28 secured in anysuitable way, as by a nut 34 to the shouldered end 35 of the rod 6. Atone end of the member 26 is a radially extending bore 23, in which ispositioned the boring tool 5, the latter being locked in position by aset screw 30. An adjusting screw 3| having a conical inner end, isarranged in the member 26 to engage the inner end of the boring tool, sothat the position of the boring tool in the carrying member may beadjusted by turning of this screw 3|, which is accessible for thispurpose through a suitable opening 3I' of the cap I'I.

The tool carrying member 26 has an inwardly-.

facing surface 32 which is opposed to the aforesaid fiat surface 38;this surface 32 is at a slight angle to the axis of spindle '2 forcooperation with a surface 33 of similar slope on the cam block 28.Thus, when cam 28 is moved by'rod 6 to the right, Fig. 1, the tool isdisposed in its operative position, by the outward movement of the toolcarrying member 26. The retraction of the boring tool is procured by theaction of the coil springs 25, when the cam 28 is shifted to the left,Fig. l, to allow the springs to force the member 26 in the otherdirection. I

The cam 23 is rigidly supported against lateral movement within the toolcarrying member 26 to vary the radial position of the boring tool, andthe collet 8 has a mark, also not shown, which cooperates with thegraduations on the member I5, and which indicates the necessary degreeof adjustment, in order that the point of the boring tool may be movedradially inward or outward a predetermined distance.

It will be noted, in connection with this provision for fine adjustmentof the tool, that the cam 28, by reason of its close confinement betweenthe surfaces 32 and 31, is invariably constrained to partake of theangular movements I imparted to the assembly in obtaining such adby theengagement between a convex surface 36 e cap extension 24, said surfaceopposing the surface 38 of tool-carrying member 26. This convexity givessubstantially a line contact between these two surfaces, in consequenceof which the position of the tool point is not appreciably affected byany variation in oil-film thickness between these opposedmovement-limiting surfaces.

The cap I! is held onto the ends of portions I51; and I 51) by bolts 39,so that said cap and the member I5, together with the movably mountedtool carrying member 26, are held in assembled relation. These bolts 39,as shown, are suitably positioned relative to the long bolts 20, whichhold the entire mechanism in assembled relation.

In addition to the coarse adjustment of boring tool 5, provided by thescrew 3|, my invention provides for a fine adjustment of the cuttingpoint of the tool relative to the spindles axis of rotation. To thisend, as above stated, the surface I3 on the collet 8 is slightlyeccentric ,(being greatly exaggerated in Fig. 4), and thereby providesfor an adjustment of the eccentricity of the member I5 by turningthis'member relative to the collet 8. It will'be noted that the memberI5 has a surface 40 cooperating with the surface I3, and that thissurface 40 is also eccentric to the center line of the member I5. Thecollet has arcuate slots 4I, through which the bolts 20 extend, theseslots permitting a turning movement of the member I5, and the partsmounted thereon, relative to the collet, so that any necessaryadjustment of the position of the cutting point of the boring tool maybe made. The periphery of the member I5 preferably has graduationsthereon, not shown, indicating .the direction for turning the member I5,in order justments; thus the tool retraction is unaffected by theadjustment, and the latter is not interfered with in any way by theretracting mechanism.

As shown in Fig. 3, the tool carrying member 26 may be held securelyagainst vibration between the portions I 5a and I5?) of member I5, by agibor filler strip 42 inserted in the passage I6 between "the members.This strip is prefer ably held in position by pins 43 in the portionI512. The portion I511 has an inwardly projecting pin 44 engaging in thenotch 21 in the member 26, which limits the amount of retraction of theboring tool by engaging with the surface 32. It may be desirable toprotect the working parts of the tool retracting mechanism from chips ordirt, and for this purpose there is provided a substantially circularcovering plate 45, which is held in position on the portions I5a and I5bby suitable pins 46.

The above described coarse and fine adjustments of the boring tool 5 arepreferably effected with the cam 28 in its right hand position, Figs. 1and 2, that disposes the tool-carrying member 26 at the limit of itsoutward radial movement. Then, in operation, after the tool hastraversed each workpiece bore, and prior to any withdrawal of the boringtool from said bore, the mechanism which has been utilized to hold therod 6 in its right-hand position, is operated, either automatically ormanually, to move the rod to the left, thereby causing the tool carryingmember 26, under the action of the springs 25, to move a littleinwardly, so as to offset the boring tool inwardly from its normaloperative position, and thereby prevent contact between the finishedsurface of the workpiece and the point of the tool, during the ensuingwithdrawal of said tool from the workpiece bore.

The mechanism by which the rod 6 is axially shifted is not a feature ofthe invention. It may be noted, however, that this rod may readily beactuated at the reversal of the'movement of the reciprocatory table orcarriage, usually provided in boring machines to obtain the passage ofthe tool endwise through the workpiece. Such a table or carriage isfrequently actuated by fluid under pressure, and this same fluidpressure under the control of the reversing means for the reciprocatorycarriage, may also be utilized for shifting the rod 6, as will beapparent.

I claim:

1. In mechanism of the class described, a rotary spindle, a membermounted on the end of said spindle for rotation therewith, a slidesupported by said member for movement radially of the'spindle, meansassociated with said member for limiting the movement of the slide inone dimotion, a boring tool carried by the slide, a rod axially slidablewithin the spindle and a cam mounted on said rod and engageable withsaid slide for moving said slide intoa position where the limiting meansare operative, said member having means for supporting the cam at apoint opposite to its engagement with the slide.

2. In mechanism of the class described, a r0 tary spindle, a headcarried by said spindle for rotation in unison therewith, a toolcarrying member slidable radially in said head, a rod slidable axiallyof said spindle, a cam on said rod, engaging said member, to procure bysaid rods movement in opposite directions, the operative positioning andthe retraction from operative position, of the tool carried by saidmember, said head being eccentrically mounted on said spindle forangular adjustment, to vary the projection of said tool from the spindleaxis, and means for constraining said cam to move angul-arly, in unisonwith the adjusting movement of said head.

3. In mechanism of the class described, a rotary spindle, a headattached to said spindle for rotation in unison therewith, 'said headbeing eccentrically mounted on said spindle, a toolcarrying memberslidable radially in said head, a tool in said member whose operativeposition is varied by angular movemenftof said head on said mounting, arod axially slidable in said spindle, a cam on said rod to impartoutward radial movement to said member, thereby to operatively positionthe tool, when saidgrod is moved in one direction, a spring forproducing inward radial movement of said'member ;to retract said toolwhen the rod is moved in the? other direction, and means for procuringangular movements of said cam and rod in unison with said angulartoolad'justing movements of said head.

WALDO J. GUILD.

